


My Girlfriend's Brother

by TheRealCinnamom



Category: Haikyuu!!
Genre: Cheating, Don't get caught, Established Relationship, Kitchen blowjob, M/M, cheating with a sibling, daishou has a dick piercing bc i said so, might give off dubcon or coercion vibes so dont read if ur not into that
Language: English
Status: Completed
Published: 2020-11-15
Updated: 2020-11-15
Packaged: 2021-03-09 22:53:59
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,116
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27574091
Author URL: https://archiveofourown.org/users/TheRealCinnamom/pseuds/TheRealCinnamom
Summary: Daishou cheats on Mika with her brother.
Relationships: Daishou Suguru & Mika's Brother, Daishou Suguru & Yamaka Mika, Daishou Suguru/Mika's Brother, Daishou Suguru/Yamaka Mika
Comments: 2
Kudos: 6





	My Girlfriend's Brother

**Author's Note:**

> Me: idk i don't really like cheating fics and its not something i ever see myself interested in-  
> Furudate sensei: Mika has an older brother  
> Me: 👀👀 hmm, you don't say...
> 
> Anyway,,, enjoy LOL
> 
> (All characters mentioned are 18+,,, and no I don't know when this would take place in a canon-compliant world,, timelines are nonexistent lol)
> 
> **Final TW: This might give off slight dubcon/coercion vibes so please don't read if you're not into that**

It was late.

Daishou quickly stepped down the hall, one hand on the wall and the other held out in front of him. He could barely see where he was going as he hadn’t waited for his eyes to adjust to the darkness yet.

Thankfully, he made it to the kitchen in one piece, and lowered the arm he’d been using as a potential buffer.

The half-moon wasn’t bright, but it was bright _enough_ to where he was able to tell apart the cabinets from the empty wall space.

He winced at the sound of the faucet squeaking, glanced in the direction in which he’d came.

Mika had invited him to join her family for a weekend trip to Kyoto, and, as usual whenever Daishou slept somewhere new, he was having trouble falling asleep and _staying_ asleep.

He’d been tossing and turning for a few hours now and the last thing he wanted to do was to wake up Mika, so he had quietly made his way to the kitchen for a drink and a small snack.

But, apparently, he hadn’t been quiet enough.

“You’re not gonna lay a hand on my sister, are ya?”

Daishou gasped at the deep voice directly behind him, almost dropped the glass of water in his hand. He stepped back as he quietly cleared his throat, trying to soothe the underlying urge to cough.

Mika’s older brother just tilted his head with a smile, said nothing else as he waited for an answer. Daishou was thankful that Kiyoshi hadn’t turned the light on, so he couldn’t see how red his face was.

“No, of course not. I’d never hurt Mika.”

“Well, you already did, once. Who’s to say you won’t do it again?”

Kiyoshi stepped closer, and Daishou had no choice but to back up against the fridge. He frowned at the question, but bit his tongue as he thought over his response.

Clearly, Kiyoshi wasn’t his number one fan, and Daishou didn’t want to say the wrong thing and make it worse.

“I- that was mutual- that’s _different_.”

“Is it?” Kiyoshi smirked, brought a hand to hold Daishou’s jaw.

Daishou’s frown deepened, but he resisted the urge to push him away.

What the hell was this guy’s problem?

Sure, he was Mika’s older brother, but this was overkill.

Kiyoshi lifted Daishou's chin. “You don’t recognize me, do you?”

“ _What_? Do you mean _apart_ from the fact that you’re-”

“ _Shh_ , not so loud...” Kiyoshi lowered his hand, but didn’t put space between them. “Wouldn’t want to wake anyone up, now, would we?”

Daishou was about to bark out another witty reply, but a thigh being pressed against his crotch stopped him in his tracks. He froze as Kiyoshi lessened the distance between them even more, his lips moving dangerously close to his ear.

“Maybe this can help you remember?”

His voice was quieter, deeper, scratchier now, and Daishou swallowed hard as his statement ran true.

No way.

 _Mika’s brother_ was the one night stand he had a few months ago?

No, he wasn’t... he couldn’t be.

“What’s wrong? Don’t tell me you’ve gotten shy.”

Daishou wanted to say something, _anything_ , but it felt like his lungs had been ripped out and there was a hand squeezing tighter and tighter around his throat.

 _No_ , he wanted to say, _Mika and I are a couple again_.

Daishou took in a sharp breath when Kiyoshi pressed his thigh harder against him, and Daishou instinctively reached for his arm. He couldn’t stop himself from chasing after the small burst of pleasure, even though everything inside him was shouting otherwise.

“Good boy.” Kiyoshi chuckled.

Daishou looked away, bit his lip in effort to quiet the pleased whine that bubbled up. He screwed his eyes shut when Kiyoshi’s hand returned to his jaw.

“Look at me.”

“ _Mm-mm_.”

“C’mon...” Kiyoshi moved the palm of his hand to Daishou’s cheek. “I know you want to; don’t think I can’t _feel_ how excited you are right now.”

Daishou could taste blood at how hard he was biting his lip, and he didn’t realize he was still holding the glass of water until Kiyoshi’s hand covered his.

His fingers were gentle as they pried the glass from his hand, but he still didn’t open his eyes. Kiyoshi pressed his body flat against Daishou’s, and a few seconds later, he heard the glass being placed on the counter.

Daishou still didn’t move. He wasn’t sure if it was out of fear, arousal, denial- or maybe something else entirely. What he did know, was that he wanted this to be over as quickly as it started.

Kiyoshi leaned forward and teased Daishou’s lips with his own. His hand was still on his cheek, thigh still pressed against his crotch.

“If you want me to stop, all you have to do is ask.”

Daishou took a shaky breath.

This was wrong.

He shouldn’t be doing this.

All he had to do was push him away, tell him never to pull anything like this ever again, and go back to Mika’s room to sleep it off.

_Just say stop, and he’ll stop._

Daishou’s eyes flickered down to Kiyoshi’s lips, and the man smiled.

“Don’t want me to stop?”

Daishou ignored the shame that flooded his face as he shook his head, and a small gasp left him when Kiyoshi started moving his thigh against him.

“Say it out loud.”

“... no.”

“No what?”

“N... don’t stop.” Daishou whispered.

He was so quiet that he was worried he’d only thought it, but Kiyoshi moved closer and finally pressed their lips together. The thigh against his crotch was replaced with a hand and Daishou whined in the back of his throat.

He ignored the stupid smile that grew on Kiyoshi’s face and grabbed a fistful of the man’s shirt.

“What were you... what did you-” Daishou hissed through his teeth when Kiyoshi grabbed him through his pajama bottoms.

“Can I suck your pretty cock again?” Kiyoshi pulled him out and stroked him a few times as he sunk to his knees. “D’you still have that piercing-”

“Shut up.” Daishou looked away, into the darkness of the connected living room.

A deep chuckle left Kiyoshi’s throat, a puff of warm air leaving his lips before they wrapped around him. Daishou bit his lip when Kiyoshi’s tongue started playing with the metal bar, swirling in circles before pressing flat against it.

Daishou let the back of his head rest against the fridge, and he struggled to contain his annoyance when Kiyoshi pulled off.

“D’you get this for you or Mika?”

Daishou frowned. “Don’t talk about Mika.”

Kiyoshi hummed with a smile. “Why not?”

“I... just don’t. It’s weird.”

Kiyoshi brought a hand to Daishou’s cock to start stroking him again. “Weirder than your girlfriend’s brother sucking you off in the kitchen at two in the morning?”

Daishou didn’t respond. Instead, he grabbed a fistful of Kiyoshi’s hair and guided his dick to his lips again.

“I thought I told you to shut up.”

Kiyoshi opened his mouth to give another witty response, but Daishou didn’t let him. He took the opportunity to shove his dick down Kiyoshi’s throat instead.

One of Kiyoshi’s hands flew to Daishou’s wrist when he choked a little, but he didn’t try to pull off, so Daishou tightened his hand in Kiyoshi’s hair and proceeded to fuck his throat.

He tilted his head up to the ceiling, bit his lip to keep himself quiet.

The last thing he wanted was for Mika to wake up and see this.

Daishou knew she was a light sleeper, so her parents probably were too.

God, that’d be even worse.

“ _Fuck_ -” Daishou hissed when Kiyoshi swallowed around him, his hands moving to Daishou’s hips.

Daishou lessened the grip he had in his hair to allow the man more freedom, bucked his hips when Kiyoshi’s tongue returned to swirl around the piercing.

For a moment, Daishou wondered how it felt; having a pierced dick shoved down your throat without warning- it was probably why he had started choking in the first place.

Mika didn’t like giving head, and Daishou was fine with that, but he couldn’t help his curiosity. Kiyoshi seemed obsessed with it, and the pleasure in the pit of Daishou’s stomach only continued to build.

He came suddenly, mouth open in a silent gasp and his hand fisted Kiyoshi’s hair tighter. Even at such short notice, Kiyoshi must have been expecting it because he eagerly swallowed every last drop; even licked him clean after.

Daishou was breathless when Kiyoshi returned to his feet, didn’t argue or push him away when he leaned down to kiss him. Daishou didn’t even care about the salty taste of his own cum on Kiyoshi’s lips, or how the embrace he was pulled into seemed a bit _too_ romantic for what had just taken place between them.

“... sleep with me.”

Daishou blinked, wondering if he heard him right. “What?”

“Spend the night in my room...” Kiyoshi ran his hands up and down Daishou’s sides, moved his mouth to his ear. “You don’t want to wake Mika up, do you?”

“... no... but... won’t they- won’t they think it’s weird...?”

“No...” Kiyoshi placed his hands on Daishou’s waist, gently leading him out of the kitchen. “... we were just talking and fell asleep... what’s weird about that?”

Daishou still wasn’t entirely convinced, but felt too tired to bicker back and forth with him- and he _really_ didn’t want to wake up Mika... she was scary when she didn’t get enough sleep.

“You awake enough to fuck?”

“ _What_? _No_ , I’m going back to-” Daishou pushed against Kiyoshi’s chest as he was walked backwards into the bedroom.

“ _Shh_ \- I’m kidding, I’m kidding...” Kiyoshi closed the door behind him, smiled as he leaned back against it.

Daishou crossed his arms, fought the yawn that threatened to come out. He could barely make out Kiyoshi’s face as he walked closer to him, turned his head away when he leaned down to kiss him.

“This isn’t happening again.”

“Okay.”

“I’m serious.” Daishou frowned as he was walked backwards.

“Okay.”

The back of Daishou’s legs hit the bedframe and he fell back onto the firm mattress. “I don’t think you’re listening to me.”

“I’m not.”

Daishou scoffed in response, turned to pull back the top edge of the comforter. He could _hear_ the smile in Kiyoshi’s voice.

“Don’t touch me.” Daishou whispered, weakly shoved the older man away when he tried to continue kissing him.

“C’mon, I just wanna cuddle...” Kiyoshi slung an arm and a leg over him, pulled him close so they were back to chest under the blankets. “Doesn’t this feel nice?”

“... shut the fuck up.” Daishou mumbled, tucked his hands under the pillow.

Kiyoshi chuckled, then sighed contently. He moved his hand up and down Daishou’s forearm a few times, before pausing at his wrist to draw lazy circles.

At first, Daishou found it ticklish and annoying, but when combined with the slow, warm puffs of air against the back of his neck... it was almost like a silent lullaby.

When he opened his eyes, Daishou wasn’t sure if he was actually awake or still dreaming. It was sunny, yet he felt a chill run down his spine. He shivered under the blanket, then pulled it up and over his head.

A familiar voice rang in his ears.

“... up, Suguru, we made breakfast.”

Daishou whined in the back of his throat, and made no move to get up until the memories of last night came rushing back to him.

Was he still in Kiyoshi’s bed?

Did last night really happen?

“C’mon, sleepy head!”

Daishou squinted at the harsh light when the blanket was pulled down. Eventually, he was able to focus on Mika’s smiling face staring down at him.

“Good morning!”

“G’morning...” Daishou couldn’t hold back a yawn, his arms reaching above his head as it developed into a stretch.

“... didn’t know you knew Kiyoshi that well.”

Before Daishou could answer, a deep voice spoke up from near the doorway.

“You’d be surprised at how well we know each other.”

Daishou only glared at Kiyoshi when Mika looked over at him. Her brother’s smile grew as he glanced between them, before settling back on Mika.

“Want to know the details?”

“I think it should stay between us.”

Daishou made sure to keep his voice and expression void of any emotion, so that Mika wouldn’t pick up on the double meaning.

Kiyoshi faked a pout. “You’re no fun.”

Daishou didn’t respond, and didn’t acknowledge Kiyoshi again for the remainder of the day either.

Yet, somehow, he still ended up in his bed for a second night in a row.

**Author's Note:**

> Thank you for reading 💞💞💞 comments and kudos make my heart go weewoo!!
> 
> I don't think we know siblings' names?? So everyone say thank you to LiLi for giving me name suggestions :3
> 
> If you enjoyed reading,[ please consider giving this fic a RT on twitter!!](https://twitter.com/therealcinnamom/status/1327930789883875328) I would appreciate it a lot!! I love QRTS especially 😍😍


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